The present invention relates to a system mounted on a vehicle for collecting and storing diagnostic information of mobile objects, such as vehicles, railway vehicles and aircrafts, in a highly reliable manner and at low costs.
Electronic control of vehicles has been developing while further improvement of safety performance and environmental performance of vehicles has been required. In the electronic control of vehicles, control information is transmitted and received between Electronic Control Units (ECUs) via a control network represented by a CAN (Controller Area Network) and control is performed in cooperation and in coordination among the ECUs.
In such a vehicle electronic control system, diagnostic information relating to irregularities and failures is stored in each ECU, and the stored diagnostic information is typically retrieved at maintenance sites of dealers or the like using a maintenance tool and is used for the analysis of problems or the like.
However, the amount of diagnostic information that can be stored in the ECUs is limited and context information such as timing of events, around the diagnostic information that took place at another ECU cannot be collected later. Therefore, only the diagnostic information collected by the maintenance tool has not been sufficient enough to help quickly grasp failure factors and solve problems.
As a remedy, vehicle diagnostic equipment has hitherto been proposed that continuously monitors and stores diagnostic information in a vehicle. In JP-A-2004-9878, for example, a vehicle navigation system is described that doubles as the vehicle diagnostic equipment, and collects data indicating states from an engine control computer or the like to accumulate and store the collected data in a memory at a predetermined period.